"Touch screen devices, such as smartphones, lack a suitable method for text input which can compete with mechanical keyboards," Krautli is quoted as saying in a press release from Goldsmiths, University of London, where he is studying cognitive computing. "The Vibrative Virtual Keyboard aims to appease the frustration felt by smartphone users when faced with drafting lengthy e-mails or notes on a small onscreen keyboard."

The phone picks up vibrations from his fingers as he taps on invisible keys on the table. Using an app called Sensor Monitor, which appears in the video below, Krauti can pick up and measure those vibrations using the iPhone's accelerometer, a sensor built into the phone. A piece of software he created translates those vibrations -- which are slightly different based on their proximity to the phone -- into text on the screen. In the video demo, this does not happen seamlessly or quickly, but a spell checker picks up on the mistakes.

The software does require you to train it, according to Fast Company:

The software he coded analyzes this sensor output on a networked Macbook. All the user needs to do is train a new surface -- tap a few points and let the software know what letter those taps are supposed to be -- and Kräutli’s software will number-crunch the positions for the rest of the keys. A user can then save this surface so the software won’t need a calibration for it again.

Blogger Mark Wilson raves about the virtual keyboard's potential:

Kräutli’s creation is a remarkable statement about the future of user interfaces, where conceivably, every surface becomes a conduit for digital input.

That's the hope. But it may be quite some time before that vision becomes reality. It's also worth noting that several other companies and innovators are working on similar projects that have been getting buzz in the tech world. The big dog in this space is Microsoft, which demoed its Skinput system in 2010. It works much like Krautli's keyboard, but it turns your arm into the keyboard.

Here's a video of that technology in action:

Another cool concept comes from Jay Silver. His MaKey MaKey project turns bananas into pianos, or beach balls into a computer mouses. Here's a quick video example of that second idea:

The kit exploits the fact that by touching things you complete electric circuits. The MaKey MaKey circuit board connects to your computer via a USB cable. Then attach any object to the board using a crocodile clip. When you touch the object, you complete the circuit, and the circuit board sends a message to your computer, which thinks that MaKey MaKey is a standard keyboard or mouse. You can assign up to 18 mouse and keyboard inputs to any object.

So the bottom line seems to be this: Who knows what computer keyboards will look like in the future? Popular keyboards of the day -- those on smartphone touchscreens or the tactile, older-school versions -- may not disappear.

But, from banana pianos to table-tapping apps, there likely will be plenty more options -- ideally in the not-too-distant future.